Plywood sheets are fabricated by laminating a plurality of relatively thin sheets of wood, referred to as plies, in a stacked relationship. The plies may be made from hardwoods or softwoods; and a single plywood sheet may be made entirely from hardwood or softwood; or, it may be made from a combination of the two. Plywood has a good strength-to-weight ratio, is relatively low in cost, durable, and prepared from renewable resources. Hence, plywood is widely used in a variety of constructions. In a typical plywood sheet, the plies are stacked so that the grain of the wood of some of the plies runs in a length (vertical) direction and the grain of the wood in other of the plies runs in a width (horizontal) direction. This right angle relationship of the wood grains provides a sheet having high strength in both the length and width (X and Y) directions. However, plywood of such construction has a somewhat lower strength as measured in a direction diagonal to the length and width dimensions.
As will be explained in greater detail hereinbelow, the present invention is directed to plywood sheets which incorporate one or more plies having the grain of the constituent wood running diagonal to the length and width dimensions. This allows for the fabrication of plywood having high strength not only in its length and width dimensions but also in a direction diagonal to its length and width. This type of plywood is referred to as having “omnidirectional” strength. As disclosed herein, the present invention further provides for the low cost fabrication of such omnidirectional strength plywood by providing methods for efficiently fabricating plies having a diagonal grain direction. As a result, the present invention provides for the fabrication of low cost plywood sheets having high, omnidirectional strength. Such plywood sheets have a high strength-to-weight ratio. Such sheets have a number of applications, and have particular utility in the fabrication of earthquake and storm resistant building structures. These and other advantages of the invention will be apparent from the drawings, discussion and description which follow.